How can I view more of my history in Screen on Linux?
Assuming you haven't overriden your escape sequence, you can press Ctrl-a [ to go into scrollback mode, then use the usual Page-UP/Page-DOWN or Ctrl-b/Ctrl-f to go up and down.
From the Gentoo wiki on Screen usage
When you start screen you can specify the size of the scrollback buffer with -h, so you can increase it from the default of 100 lines. However, with a currently running screen, once the data has left the buffer, it is gone.
I need to see the onscreen output "further up" than I can on my current screen. CTRL + a is supposed to put me into scroll mode inside Screen, but it's not working.
In complement to the other answers, I would point out that you may add in your ~/.screenrc file:
defscrollback 100000
termcapinfo xterm ti@:te@
where:
defscrollback 100000: set the default number of scrollback lines to100000termcapinfo xterm ti@:te@: allow terminal scrolling in either xterm or PuTTY. (screen FAQ; PuTTY FAQ)